Draglines are utilized in mining operations to strip the overburden (e.g., rocks, soil, etc.) above a seam or deposit of a material such as coal or an ore with a large bucket that is dragged across the ground. The path of the bucket is controlled with hoist ropes and drag ropes. The dumping action for conventional buckets are not directly controlled, but are instead controlled through adjusting the tension of the drag ropes through a dump rope mechanism.
Universal dig dump mechanisms exist which allow the direct control of bucket dumping action through the use of multiple hoist ropes (i.e., hoist ropes coupled to both the front and the rear of the bucket) and alternating the lengths of the hoist ropes. However, such universal dig dump systems are more expensive than a conventional system because of modifications to the boom, the addition of a split hoist drum, and extra motors and gearcases. Further, the alternating of the lengths of the hoist ropes applies alternating loads at the sheaves on the end of the boom, creating potential fatigue loading.